If you have 2 columns with data, say A and B. On column C, cell 1 enter =LEN(B1) if you want to count on the basis of the number of characters in column B, or =LEN(A1) if you want to count on the basis of the number of characters in column A.
After you enter that on the cell, press ENTER and then place the mouse on the corner of the cell and drag down to copy the formula.
Then select the column with the counts and click Sort.
